EP3496656B1 - Method for producing a prosthesis or partial prosthesis - Google Patents

Description

The invention relates to a method for producing a prosthesis or partial prosthesis, according to the preamble of claim 1

The production of prostheses is comparatively expensive and complex nowadays, even if computer support is used.

The following procedure is often used:
To record the patient's mouth, either an impression is taken or an intraoral scan is made. This detects, for example, the edentulous jaw to be fitted with the prosthesis and, for example, the toothed jaw including the patient's teeth.

Based on the oral situation, a target shape of the prosthesis is now provided by CAD, including the prosthetic teeth, which of course must match the respective antagonists.

It is particularly favorable if gnatological aspects are also taken into account, for example the chewing movement and the associated condylar joint design.

This can be checked and, if necessary, corrected by providing a corresponding model and using it in an articulator.

The actual manufacture of the prosthesis then takes place in such a way that a flesh-colored prosthesis base, for example made of PMMA with tooth cavities, is generated based on the data obtained. The teeth to be used are inserted into the tooth cavities and glued in. These can be machine-made teeth of a set of teeth. Occlusal defects must then be removed by milling or typically by grinding.

Alternatively, individually-made teeth can also be used, for example ceramic ones. Here, a pre-made blank made of lithium metasilicate is brought into the desired shape, for example by milling. The tooth thus produced is then sintered to lithium disilicate, taking advantage of the fact that there is practically no shrinkage.

Alternatively, plastic teeth can also be used, which are manufactured either additively or subtractively, that is to say, for example, by milling.

All of the methods used have in common that a comparatively complex manufacturing process, which also takes a comparatively long time, is required for a high-quality prosthesis without occlusal defects.

The solution according to the DE 10 2009 026 159 A1 referenced which milling cutters with different diameters are used for rough milling and fine milling. According to the teaching of this document, rough, fine-rough machining is to be carried out, and also pre-finishing. This process is also complex and time-consuming.

Furthermore, here is the solution according to the WO 2011/066895 A1 referenced, according to which a digital impression of a dental prosthesis is created. According to the publication, a preliminary model is made of plastically deformable material so that further adjustments can be made before the prosthesis is created as a plastic or ceramic dental arch.

In contrast, the invention has for its object to provide a method according to the preamble of claim 1, with which a prosthesis or partial prosthesis can be manufactured quickly and with high quality, in particular the manual work to be performed by the operator should be reduced.

This object is achieved by claim 1. Advantageous further developments result from the subclaims.

According to the invention, the prosthesis base is quickly rough-milled in a first step. Based on a blank disc of, for example, 98.5 mm to 100 mm in diameter, the rough shape of the prosthesis base is thus brought within 10 minutes to 40 minutes, in particular about 30 minutes, into a shape that already approximates the desired future prosthesis base, but not at all Leave less material than is required for the future denture base.

This is followed by finish milling, and only at those points where the prosthesis base later has contact with the teeth or the prosthetic dental arch according to claim 2. These areas are designed as cavities or a U-shaped recess. If necessary, the basic shape of the cavities can already be prepared using rough milling.

Finishing is carried out to a target height in accordance with the CAD-defined joint between the dental arch and the denture base. The strength of the adhesive joint is taken into account in a manner known per se.

After preparatory work has been carried out on the one hand and on the other hand only small areas of the prosthesis base, in particular the cavity areas, which for example only concern between 5% and 30% of the total surface of the prosthesis base, the corresponding finishing milling result can be achieved quickly.

If the rough prosthesis base geometry is to be rough-milled to accelerate the process, the machined area comprises around 30% -55%. of the total surface.

It is particularly favorable if there is a large difference between the milling tools used for finish milling and for rough milling. The depth of delivery The roughing cutter preferred according to the invention can be between, for example. 0.7 mm and 2.5 mm.

In contrast, the infeed depth of a finishing cutter, as is to be used according to the invention, can be between 0.1 mm and 0.5 mm,

Especially when - as is preferred according to the invention - plastics such as PMMA, which is held in the gum color, is milled, according to the invention care is taken to ensure that the milling working temperature is low. For example, rough milling can be carried out with a preferably single-edged cutter with a diameter of 0.8 to 5 mm at 20,000 rpm to 25,000 rpm, while finish milling with a cutter with a diameter of 0.5 mm to 2, 5 mm can be worked at a speed between 25000 rpm and 30000 rpm. Fissures, e.g. in the occlusal surface of molars, can be produced with fine finishing cutters with a diameter of 0.5 to 0.7 mm.

A particularly serious cost and time reduction in the manufacture of a prosthesis or partial prosthesis can be provided according to the invention by realizing a prosthetic dental arch from a tooth-colored blank. The blank can, for example, also be designed in the form of a disk, it being possible for two or even more dental arches to be accommodated on a blank disk with a diameter of 100 mm. Alternatively, it can also be milled from an essentially U-shaped blank. The blank is first machined by rough milling - expediently using the same roughing mill as mentioned above - and brought into the essential U-shape.

An essentially U-shaped dental arch can be produced from a blank for later provision of teeth from a tooth-colored material, in particular PMMA with fillers. The manufacture can be carried out in any suitable manner, e.g. by milling or by means of a pressing process.

Instead, the dental arch semi-product can also be produced by injection molding or compression molding or any other molding process. It is It is also possible to prefabricate the dental arch as a quarter product with additional oversize by injection molding, and then to pre-mill the semi-finished product with a nominal oversize in the desired size according to the patient's dental arch, eg "small", "medium" and "large" finished milling.

The semi-product is preferably made with the retaining webs left and with an oversize compared to the teeth of the prosthesis, in particular by rough milling. The basal region of the dental arch, i.e. the basal surface and the adjoining surfaces, are prepared for inclusion in a prosthesis base. For this purpose, the basal region is brought into an essentially trapezoidal cross section.

The dental arch blank (tooth-colored blank) can have a gingival-incisal or gigival-occlusal color gradient, in particular from dark to light. The height of the dental arch in the blank is preferably determined by CAD / CAM, specifically at the user's choice, so that the actual color range and / or brightness range of the dental arch is thereby determined,

The dental arch and / or the dental arch blank can also be in several parts, e.g. be in three parts, with 2 molar and one anterior partial dental arch.

In this case, it is sufficient if only the anterior arch has a gradient.

However, the tooth shape is not yet provided. Only the basal surface of the teeth of the blank is brought into the desired shape by roughing and finishing, and, if necessary, adjacent areas of the dental arch or teeth. These areas are preferably designed as inclined surfaces that extend at an angle of 100 ° to 170 ° to the basal surface and converge towards the basal surface.

The angular design, the course and the other geometrical design of this gingival region of the dental arch is exactly in line with the tooth cavity of the prosthesis base adjusted, leaving an adhesive gap, which can be, for example, 0.150 mm, or a suitable value between 0.08 mm and 0.22 mm.

Here, too, only a small area of the entire outer surface of the dental arch, for example 30% to 50%, is subjected to finish milling, so that the CNC milling machine to be used does not take a long time to produce the desired precise contact surfaces. All the more so since rough milling was also used here.

After the dental arch and the dental cavity of the denture base have been created, the facing surfaces - either one of these or both - are provided with a suitable adhesive. Before that, the surface is enlarged, for example by means of sandblasting or by milling in certain structures such as grooves, elevations, depressions and / or geometric patterns on the basal side of the dental arch or the tooth cavities of the denture base.

The adhesive can also be applied while the prosthesis base is clamped in the CN-C milling machine by opening the door to the milling room and the operator carrying out the corresponding processing.

Alternatively, of course, the prosthesis base or dental arch can be removed and treated there accordingly.

After both parts have been prepared, they are in any case provided with adhesive in the areas which will later adhere to one another. For this purpose, an adhesive joint of e.g. 0.12 mm is provided. The parts are then fixed, for example via a transfer matrix, until the adhesive has hardened.

While special clamping holders can be used for curing the adhesive, which hold the combination of dental arch and denture base clamped in during curing of the adhesive, it is also possible to use the denture base to be clamped again in the milling machine or to be left clamped in it and after inserting the dental arch to press it against a counter pressure surface without further ado, so that a contact pressure is also exerted during curing.

Pressing causes the adhesive to swell out of the joint, at the transition area between exposed areas and contact areas of the dental arch, the so-called gingival margin. The transition area between the dental arch and the denture base is free of an oversize. The gingival margin is therefore exposed, but is covered by excess glue.

The adhesive gap is completely filled with adhesive. The adhesive swells out of the gap on both sides and forms an excess of adhesive or jointing compound there. This is removed during the final finishing step.

Subsequent to curing, the prosthesis base together with the inserted teeth or - preferably - the inserted dental arch, is clamped again in the workpiece holder of the milling machine or remains clamped there.

The milling machine is preferably designed so that an automatic tool change of the different roughing and finishing cutters is possible.

At this point in time, the base of the prosthesis is preferably still connected to the rest of the blank disc with retaining webs. Alternatively, it is also possible to hold the prosthesis base itself clamped by means of appropriately designed workpiece holders.

An - optional - roughing milling step then takes place, with a possibly finer roughing milling tool with infeed depths between 0.7 mm and 2.5 mm. This is used to prepare the finishing, so that the time for finishing is further reduced

Any adhesive beads, which are caused by adhesive that oozes out, are automatically removed in the final milling step.

In this last step, which can possibly also be carried out without the roughing-milling step mentioned above, both the tooth area and the prosthesis base area are now milled to the desired target shape. This can also be done overnight if this makes sense from the process flow after no user intervention is required during this last step.

If inaccuracies, e.g. with regard to the altitude, they are automatically corrected using the final milling step. This can take place automatically, as it were: The CAM software stores a target shape for the occlusal surface and the other exposed tooth surfaces based on the CA-D data.

If the dental arch or dental arch is glued in "obliquely", so that there is a glue error, the finishing is nevertheless carried out according to the target, so that occlusal defects per se are avoided.

The prosthesis is then polished, e.g. for 10 min.

The finished prosthesis is now available and can be removed from the CNC milling machine.

The material used is preferably adapted to the requirements both for the dental arch and for the prosthesis base. For example, a somewhat harder PMMA plastic material or a material made from a combination of PMMA and inorganic or organic fillers, the strength / hardness of which is greater than that of the base material of the prosthesis, can be used for the dental arch. The filler content of the dental arch material is 10 to 30% by weight, preferably about 20%.

While milling tools with a larger diameter than roughing cutters and with a smaller diameter than finishing cutters are preferably used for rough milling, this is not immediately necessary; it is also possible that the diameter of a finishing cutter may exceed that of a roughing cutter in individual cases.

In the gluing process, it is also possible to keep the prosthesis base and the dental arch separately and at a certain predetermined distance that corresponds to the desired optimal thickness of the glue joint. A kind of fine tuning can then also be provided here, namely by adapting the height of the dental arch relative to the prosthesis base and, if appropriate, also the lateral position and the angular position to the requirements. In this embodiment of the invention, the adhesive joint represents a means of avoiding or reducing any occlusal defects. This also eliminates the need to fit e.g. check in the articulator.

It goes without saying that when inserting and reinserting the workpiece, i.e. the dental arch or the prosthesis base, regardless of the respective processing state as a blank or as a semi-finished product, markings can be used in a manner known per se, which enables the exact position of the Secure the workpiece to the clamping device of the milling machine.

Such markings are preferably made at locations which are not milled away or, if appropriate, are milled away only in the last finishing milling step.

The rough milling is preferably carried out very roughly, ie only in the vicinity of the target shape, and the oversize can fluctuate, both within the prosthesis base or the dental arch and from specimen to specimen. The fluctuation range can be between 0.2 mm and 1.5 mm.

By using larger roughing cutters and by using a significant feed, which is slightly below the material load limit, the roughing milling time is drastically shorter, for example a third of the finishing milling time.

The workflow in the dental laboratory or in the dental practice is significantly improved by the short roughing milling time, after which an interaction with the operator is necessary, which represents a significant advantage of the invention.

In a manner known per se, the CAM software can control both roughing and finishing milling. It is also possible to monitor the material temperature with an appropriately equipped milling machine with a temperature sensor in order to comply with the load limit of the material. In a manner which is also known per se, the tool change and the workpiece change take place automatically, so that only the gluing remains as an activity which at least partially requires user intervention.

It is particularly expedient if both the prosthesis base and the dental arch remain connected to the rest of the blank initially via retaining webs. This makes it possible to avoid a special holder for the semi-finished parts. Only at the last possible point in time are the holding webs removed, for example for the dental arch when glued into the tooth cavity of the prosthesis base.

On the other hand, the retaining bars for the denture base can only be removed after the final finishing step.

The shape of the interconnected cavities for the dental arch can be adapted to requirements in a wide range. For example, the channel or tooth cavity, as it can also be called, can be flatter in the molar region and deeper in the anterior region. This can be associated with a corresponding change in the angle of the inclined surfaces, so that steeper inclined surfaces are used in the anterior region than in the molar region.

The depth of the tooth cavity can also be adapted to the requirements in a wide range, as can the width. Here, too, there can be a change in the course of the dental arch.

In an advantageous embodiment, it is provided that the accumulated roughing milling time is less than half and particularly preferably less than one third of the accumulated finishing milling time and that the finishing milling is controlled in particular overnight using CAM software.

In a further advantageous embodiment, it is provided that dental arch blanks (10) and denture base blanks are inserted into the workpiece holder in the same milling machine, in particular each in the form of a disk, and that, if necessary, the tool is automatically changed from a roughing cutter to a finishing cutter .

In a further advantageous embodiment, it is provided that after preparing the basal surfaces (20) and the surrounding areas of the dental arches or partial arches by finishing and preparing the cavities in the prosthesis base for receiving the dental arches or partial arches on one or both of the opposing, Surface adhesive is applied, in particular by machine, and particularly preferably while at least one of the parts to be glued is held clamped in the milling machine.

In a further advantageous embodiment, it is provided that after application of the adhesive, the parts to be bonded to one another are held in a manner known per se during curing, in particular in the milling machine, the workpiece holder of the milling machine pressing the prosthesis base and the dental arch (14) glued into it Back pressure area presses and so the adhesive holding force applies.

In a further advantageous embodiment, it is provided that at least two dental arches (14) made of tooth-colored material are accommodated on a blank (10) or, if appropriate, a plurality of dental arches.

In a further advantageous embodiment, it is provided that the dental arch blank (tooth-colored blank) has a gingival-incisal or gigival-occlusal color gradient, in particular from dark to light, and that in particular the height position of the dental arch determined by CAD / CAM in the dental arch blank Choice of the user defines the color range and / or brightness range of the dental arch, In a further advantageous embodiment, it is provided that upper jaw dental arches are prefabricated in a more spherical shape than lower jaw dental arches, while lower jaw dental arches are slimmer.

The method according to the invention results in considerable milling time savings and also a reduction in tool wear.

The used material can be reduced by pre-shaped dental arches in different sizes. Furthermore, retaining webs / holders for CAM devices can be provided on the preformed dental arches, which replace the necessary cost-intensive disk holders.

It is particularly favorable that the milling time is considerably reduced by the milling strategy, i.e. rough milling of essential parts, finishing milling of the transition areas, joining, then possibly milling again, then final layer milling.

According to the invention, it is particularly favorable that the dental arch can be glued in the prosthesis base much more easily compared to the gluing of individual teeth into the prosthesis base. The large-area support also optimizes the adhesive strength.

Further details, advantages and features result from the following description of several exemplary embodiments with reference to the drawings.

Fig. 1

eine schematische Ansicht eines Zahnbogen-Rohlings mit bereits teilausgefrästem Zahnbogen;

Fig. 2

ein Rohling für zwei Zahnbögen, die bereits - abgesehen von den Haltestegenschruppgefräst sind;

Fig. 3

eine Draufsicht auf einen aus der Rohlingsscheibe heraus gelösten Zahnbogen bzw. vorgeformten Zahnbogenrohling, wobei die Haltestege noch vorhanden sind bzw. vorgesehen sind;

Fig. 4

ein Schnitt durch den Zahnbogen entlang der Linie IV-IV;

Fig. 5

eine schematische Ansicht eines Prothesenbasis-Halbfabrikats;

Fig. 6 a und 6b

geschruppte Zahnbögen mit zu schlichtender Basalseite von vorne und von unten ; und

Fig. 7

eine Ansicht eines beispielhaften Schruppfräsers.

Show it:

Fig. 1

a schematic view of a dental arch blank with already partially milled dental arch;

Fig. 2

a blank for two dental arches, which are already milled - apart from the holding bar roughing;

Fig. 3

a plan view of a dental arch detached from the blank disc or preformed dental arch blank, the retaining webs still being or being provided;

Fig. 4

a section through the dental arch along the line IV-IV;

Fig. 5

a schematic view of a prosthetic base semifinished product;

6 a and 6b

roughed dental arches with basal side to be finished from the front and from below; and

Fig. 7

a view of an exemplary roughing cutter.

Fig. 1 shows a schematic representation of a dental arch blank disc 10. The dental arch blank disc has a diameter of, for example, 98.5 mm and a height of 20 mm, it being understood that these dimensions can be adapted over a wide range to the requirements. In any case, the height of the disc should cover the maximum height of the teeth or dental arch to be created, including the basal region.

How out Fig. 1 it can be seen that a U is essentially milled out of the disk, with retaining webs 12 holding the U to the rest of the disk.

The milling was done by rough milling so that it could be done quickly, for example within 30 minutes.

The U is later used as dental arch 14 and has a size that is already adapted to the patient for whom the prosthesis is later intended.

A corresponding U for a lower denture base is milled out of another, gum-colored blank. This was also created by rough milling, in 15 to 40 minutes, especially in 30 minutes.

The prosthesis base also has retaining webs that connect it to the rest of the blank disc.

The milling is done in such a way that a dental arch cavity is already prepared, i.e. pre-milled using rough milling.

Both parts, i.e. the tooth-colored dental arch blank disc, but also the gum-colored denture base blank disc now each carry a semi-finished product that is rough-milled and is connected to the rest of the disc with retaining webs 12.

In this state, both parts are milled, but only in the area in which they are intended to be joined together.

m belassen.In the dental arch, the basal region 18 (cf. Fig. 4 ), and for the denture base this is the dental cavity, which can also be referred to as the dental arch cavity. The finishing is done so that the basal surface of the dental arch is brought to the final dimension. Furthermore, in the exemplary embodiment shown here, an adhesive gap of 150

leave m.

After finishing milling, the dental arch is separated from the dental arch disk by removing the holding webs 12. It is glued in the basal area, or the tooth cavity of the denture base is glued. The dental arch is then pressed into the tooth cavity with its basal region while displacing the adhesive and held in a specific position in which the adhesive is to harden.

After curing, rough milling is carried out, which in particular also removes adhesive residues generously.

In the next process step, the bonded combination of dental arch and denture base is milled. After completion, the support bars of the prosthesis base are also removed and there is an overcasting.

If necessary, it is also possible to add a polishing step if necessary.

According to Fig. 2 shows how two dental arches 14 can be accommodated in a blank disk 10.

In the illustrated embodiment, these are offset from one another and are otherwise accommodated on the disk in a space-saving manner.

Out Fig. 3 it can be seen in what way a dental arch 14 can be provided with retaining webs 12 in another embodiment.

Fig. 4 shows schematically a section through the dental arch 14 along the line IV-IV. An incisal or occlusal area 16 is rounded, in the exemplary embodiment shown rounded. Here, any design forms are conceivable, such as curved surface, which indicate fissures.

In contrast, the basal region 18 essentially has a trapezoidal shape. The basal surface 20 is flat, and starting from here, laterally basal side surfaces 22 and 24 extend away, diverging from one another towards the incisal region. At the end of these, they pass continuously.

The shape shown is intended for the canine or premolar area. In contrast, the basal region is wider and flatter in the molar region and narrower and higher in the anterior region.

This also applies to the corresponding incisal region of the dental arch 14, even if this is in Fig. 3 is not expressed in this form.

At the transition between the basal surface 20 and the basal side surfaces 22 and 24, a radius is preferably provided which is quite small, for example 0.8 mm.

Out Fig. 5 a semi-finished product of a prosthesis base can be seen in the top view. In this state, the prosthesis base 26 already has a U-shaped recess 27 which is intended for the later reception of the basal region 18, that is to say the basal surface 20 and the surfaces 22 to 24 adjoining here, of the likewise U-shaped dental arch 14.

In this state, the base of the prosthesis has not yet been separated from the blank disk 28, but this is done in the next step.

Most of the prosthesis base 26 is first rough-milled and already milled in the area of the U-shaped recess 27.

Fig. 6a shows an already arch-milled dental arch 14. The dental arch 14 already shows individual teeth 29. The teeth 29 are each connected to one another by tooth transitions 31. To this extent, the dental arch 14 is in one piece and, in the exemplary embodiment shown, comprises molars, premolars, canines and anterior teeth.

It goes without saying that a toothed part arch can also be used according to the invention instead.

In the basal region 18, the dental arch 14 is also only rough-milled in the state shown, as is also the case Fig. 6 b can be seen. It can be seen there that the basal region 18 is still quite spherical and has a corresponding oversize, while in the next step the oversize is removed by finish milling.

Milled, the basal region 18 fits exactly into the U-shaped recess 27 while leaving the adhesive joints.

Fig. 7 shows a side view of an exemplary roughing milling cutter 30. The roughing milling cutter 30 is designed as a single cutter and is diamond coated. In a manner known per se, it has a back web 32 which projects relative to the milling cutter 34 by a web height 36.

The web height 36 depends on the diameter of the milling cutter. Here, diameter is not to be understood as the diameter on the clamping shank 40, but rather that in the front area. The diameter D for the roughing cutter can be about 1 mm to 6 mm. The web height 36 is one twentieth to one sixth of the diameter D.

The roughing cutter is designed as a cutter and has a spiral groove 42 which serves to remove the milling chips.

In accordance with the invention, cutters are preferred since the tendency to clog is lowest in these.

It goes without saying that any other rough milling cutters can be used in a suitable form instead, for example also uncoated or also double cutters or optionally also ball cutters.

However, coated roughing cutters are preferably used at least for milling the dental arches.

A finish milling cutter to be used according to the invention can have essentially the same structure, with both the diameter D and the web height 36 being preferably smaller in the finish milling cutter in order to take into account the smaller infeed depth during the finishing milling step.

Milling is preferably carried out in a master / slave process: First, the optimal joint between the denture base and dental arch is calculated using CAD - taking the adhesive gap into account.

However, the minimum material thickness of the prosthesis base is used as the master: if, based on the initial design, it falls below a specified minimum value at one point, for example 1mm, 1, 5 mm or 2 mm, the parting line is changed so that the minimum value is maintained everywhere . This can also be done, for example, by changing the steepness of the basal surface of the dental arch or, if necessary, by translating it into the vestibular Direction, especially in the area of the incisors with their already greater basal surface steepness.

This procedure has favorable effects on the strength of the prosthesis base, while still providing optimal adhesive surfaces.

Claims (12)

1. A method for producing a prosthesis or partial prosthesis based on digital data, using a plurality of teeth present in a dental arch (14) or partial dental arch and a prosthesis base to be produced, wherein the prosthesis base is rough-milled by means of a milling tool, i.e. is milled in a first step, and in that the prosthesis base present as a semi-finished product, is partially, finish-milled by means of another milling tool, i.e. is milled in a second step, in particular in areas of the prosthesis base where the teeth and the prosthesis base are in contact with each other and/or are to be bonded together, and is thus brought to a target height, which target height corresponds to the contact between prosthesis base and tooth or dental arch plus the desired adhesive gap between the prosthesis base and the tooth or dental arch (14), characterized in that a dental arch (14) is glued into the tooth cavities of the prosthesis base, and, after the adhesive is hardened for bonding, is followed by finish-milling the combination of dental arch (14) and prosthesis base at all points having rough-milled areas.
2. The method according to claim 1, characterized in that a dental arch (14) is rough-milled from a tooth-colored blank in a rough-milling step and subsequently the basal surface (20) of the teeth of the dental arch (14) and, if necessary, gingival regions of the dental arch (14) adjacent thereto are finish-milled in a finish-milling step.
3. The method according to one of the preceding claims, characterized in that the dental arch (14) for making the prosthesis is made of plastic, in particular with a hardness/strength which is greater than that of the prosthesis base material and particularly preferably includes fillers, in particular PMMA bead polymer fillers and/or highly crosslinked prepolymer fillers, which are surrounded by a diffusion layer, in particular in a filling degree of 20% by weight.
4. The method according to one of the preceding claims, characterized in that the prosthesis base is milled starting from a flat cylindrical disc of prosthesis base material, and is rough-milled such that the outer contour is substantially U-shaped.
5. The method according to one of the preceding claims, characterized in that the infeed depth of the roughing cutter, when milling the prosthesis base, is between 0.7 mm and 2.5 mm, in particular between 1.0 mm and 2.0 mm, between 0.1 mm and 0.5 mm when finish-milling the prosthesis base, and/or that the infeed depth of the roughing cutter when milling dental arches or partial dental arches is between 0.6 mm and 2.2 mm, and when finish-milling the dental arches or partial dental arches is between 0.1 mm and 0.4 mm, in relation to each milling step.
6. The method according to one of the preceding claims, characterized in that roughing cutters having a diameter of between 0.8 mm and 6 mm are used as a tool, and areas to be finish-milled are previously rough-milled, and finishing cutters will be used between 0.5 mm and 3 mm, preferably equal to or less than 2.5 mm.
7. The method according to one of the preceding claims, characterized in that an adhesive joint of between 0.08 mm and 0.22 mm is present between the tooth arch (14) or the partial tooth arch and the prosthesis base, and especially the relative position of the partial tooth arches or the tooth arch in the cavities of the prosthesis base is used for height/side/angle correction of the position of the two rough-milled and partially finish-milled elements in relation to each other.
8. The method according to one of the preceding claims, characterized in that, following application of the adhesive and gluing the dental arch into the cavities of the prosthesis base and hardening the adhesive between the dental arch (14) and the prosthesis base, the dental arch (14) is finish-milled with the prosthesis base being exclusively clamped into a workpiece holder of the milling machine.
9. The method according to one of the preceding claims, characterized in that the dental arch (14) is rough-milled from a blank disc (10) leaving retaining webs (12), wherein dental arches produced by rough-milling are produced, in particular inciscially, crowned and gingival in cross-section having a basal surface (20) and side surfaces (22, 24) converging thereto and having a substantial U-shape.
10. The method according to one of the preceding claims, characterized in that the basal geometry of the dental arch (14) and the associated shape of the cavity of the prosthesis base are adapted to each other, and especially are flatter and wider in the molar region, and are narrower and deeper in the incisor region.
11. The method according to one of the preceding claims, characterized in that the gingival regions of the dental arch are trapezoidally milled and preformed to form contact surfaces opposite the cavities in the prosthesis base.
12. The method according to one of the preceding claims, characterized in that substantially U-shaped dental arches are prefabricated in several sizes, in particular three sizes, and the size best suited for the prosthesis currently to be produced is selected for this prosthesis, wherein especially the substantially U-shaped dental arches have been prefabricated by means of milling or pressing, and preferably comprising holders for a CAM machine.

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